2007 classic crewcab LS model side mirrors upgrade

[07whiteclassic]

Hello all,

Been reading information off this site for a while now, but first time asking a question. My passenger side mirror cracked over the winter and I had been thinking of upgrading to the mirrors with turn signal. I finally got around to ordering a mirror, with backing plate. I had read that the wiring should be in the door, since my mirrors did not have the turn signal option. I took the whole thing apart yesterday and couldn't find anything extra. Is there a pre-wiring setup going to the door? Do I need to run a wire from the steering column? Can I just buy the wiring harness from a junkyard and run from door power unit to the mirror itself? This is where it gains power now, a 5 wire setup running from under window controls to the old mirror. Thanks for any help, I don't mind rewiring, but want to take the easiest route available first.